Syntax: Syntax refers to the arrangement of words and phrases in a sentence or line of poetry. It focuses on how words are structured and organized within a sentence.
Connotation: Connotation refers to the emotional or cultural associations that certain words carry beyond their literal meanings. It explores the deeper implications and feelings evoked by specific word choices.
Register: Register refers to variations in language based on social context, audience, or purpose. It involves adjusting one's diction according to formal or informal situations.